This application aims to facilitate research on eosinophilic esophagitis (EoE), eosinophilic gastritis (EG), and eosinophilic colitis (EC) through the development of a Consortium of Eosinophilic Gastrointestinal Disease Researchers (CEGIR). CEGIR comprises clinical centers in Ohio (the coordinating center), Colorado, California, Indiana, Pennsylvania, Illinois, North Carolina, Massachusetts, Switzerland, and Maryland. All participating domestic, non-National Institutes of Health (NIH) clinical centers are associated with a Clinical Translational Science Award (CTSA). The CEGIR sites have been carefully chosen on the basis of their preexisting record of collaboration with each other; diverse expertise in relevant clinical specialties including Gastroenterology, Allergy, Immunology, and Pathology; the ability to integrate pediatric and adult patients into a common consortium; and well-established record of excellence in clinical research involving this patient population. Importantly, the CEGIR sites have proven access to an adequate number of patients with the rare diseases studied, as evidenced from the recent completion of the first set of controlled clinical trials involving this patient population. Strong patient advocacy groups (PAGs), including the American Partnership for Eosinophilic Disorders (APFED) and the Campaign Urging Research for Eosinophilic Disease (CURED), already partner with the CEGIR Investigators and will continue to work synergistically in the context of CEGIR. Despite the recent record of advances by CEGIR Investigators, the early success of their collaborative interactions, the proactive PAGs, and the development of novel anti-eosinophil therapeutics, there is no currently existing funding for a clinical network focusing on these three rare, distinct diseases, highlightig the timeliness and importance of this application.